The hypothesis being tested is that percutaneous penetration of imiquimod occurs following three-times per week application to genital warts. This is a phase I special metabolism trial to evaluate the percutaneous penetration of imiquimod 5% cream when it is applied three times per week for a maximum of 16 weeks to patients with genital warts. Patients will be hospitalized (for 48-72 hours) after the first dose, after 4 weeks of treatment and at the end of therapy for blood and urine samples. Between hospitalizations they will be seen twice monthly as outpatients. Since imiquimod will be marketed for treatment of genital warts in 1997, the significance of this study is the determination whether this drug and/or its metabolites appear in detectable levels in the serum and/or urine after topical application.